Utilization of stored energy reserves during fasting varies by age and season in Steller sea lions
Abbreviated Journal Title
Can. J. Zool.-Rev. Can. Zool.
HYDROGEN-ISOTOPE-DILUTION; MIROUNGA-ANGUSTIROSTRIS PUPS; ARCTOCEPHALUS-GAZELLA PUPS; BODY-COMPOSITION CHANGES; EUMETOPIAS-JUBATUS; FUR SEALS; PROTEIN CATABOLISM; METABOLIC-RATE; HARBOR SEALS; CALLORHINUS-URSINUS; Zoology
Nine captive Steller sea lions (Eumetopias jubatus (Schreber, 1776), 1.75-6 years of age) were fasted for 7-14 d to test the effect of short-term fasting on changes in body mass and body condition. Trials were repeated during both the summer breeding season and the nonbreeding season in seven animals to elucidate whether there was a seasonal component to the ability of Steller sea lions to adapt to limited food resources. Mean percent mass loss per day was higher during the breeding season in juveniles (1.8% +/- 0.2%center dot d(-1)) than in subadults (1.2% +/- 0.1%center dot d(-1)), but there were no significant age-related differences during the nonbreeding season (juveniles, 1.5% +/- 0.3%center dot d(-1); subadults, 1.7% +/- 0.3%center dot d(-1)). A decrease in the rate of mass loss occurred after the first 3 d of fasting only in subadults during the breeding season. Percent total body lipid ranged from 11% to 28% of total body mass at the initiation of fasting trials. Animals with lower initial percent total body lipid exhibited higher subsequent rates of mass loss and a lower percentage of tissue catabolism derived from lipid reserves. There was no evidence of metabolic adaptation to fasting in juveniles, which suggests that juvenile sea lions would be more negatively impacted by food limitation during the breeding season than would subadults.
Canadian Journal of Zoology-Revue Canadienne De Zoologie
"Utilization of stored energy reserves during fasting varies by age and season in Steller sea lions" (2007). Faculty Bibliography 2000s. 7559.